With the development of coding and information compressing technologies and the rapid development of digital networks, the videoconferencing system has started to enter the market. With the rapid development of IP networks, the videoconferencing system that is based on H.323 Videoconferencing Standard has been increasingly widely applied. Governments, and enterprises have generally deployed videoconferencing systems of their own, so as to enhance the efficiency of conferences and to lower the cost of conferences.
Video conference has developed from the simple modes of point-to-point session and display of the other parties' videos by a single screen to the currently sophisticated modes of one conference held simultaneously in several conference halls, multi-picture displays, or multi-screen displays at the same time. When pictures coming from different conference halls form a single multi-picture display, or when several conference halls are simultaneously outputted for display by a plurality of display devices, because the different conference halls are subjected to influences of site environments and such conferencing equipments as lightings and camera pickups, video environments are rendered different, particularly in terms of chroma and luminance that would exhibit differences, in which case, if pictures of different conference halls are formed into a single multi-picture or outputted and displayed via a plurality of display devices, the conventioneers would have the feeling of not uniform and harmonious, and visual experience would be reduced.
In order to reduce the aforementioned influences and improve the visual experience of conventioneers, the related art provided the following two solving schemes.
Scheme A:
Picture Adjustment at the Source Terminal—whereby before a picture of a certain conference hall is outputted to target conference halls, effect is adjusted at the conference hall input terminal. For instance, each of conference halls A, B, C and D individually adjusts parameters of its respective video collecting devices, for example by adjusting the color and luminance parameters of the camera pickups, or by improving the effects of respective conference hall pictures through automatically adjusting functions supported by the camera pickups, to thus ensure that the pictures be outputted to the target conference halls to be spliced as a multi-picture only after the effects of respective conference halls become optimal.
However, there are differences in video collecting devices of the conference halls, and site environments of the conference halls are also not identical due to influences such as strong and weak lights and colors of lightings—for instance, a certain conference hall uses lamps of cold tone, and the lights of the entire conference hall will assume the cold tone; a certain conference hall uses lamps of warm tone, and the lights of the entire conference hall will assume the warm tone. According to technical means provided by Scheme A, when conference halls separately adjust their picture effects, environment differences with respect to other conference halls will not be taken into full consideration, and thus, when pictures of the various conference halls are gathered to be spliced into a single multi-picture, luminance and color characteristics of various sub-pictures in the multi-picture will be starkly different from one another, thus deteriorating visual experience.
Scheme B:
Adjustment of Outputted Picture—whereby effect is adjusted at the conference hall output terminal. For instance, when a single multi-picture is received at a multi-picture conference, various sub-pictures are simultaneously modified by adjusting the output modes (parameters such as color and luminance) of the display device, to uniformly adjust the output effect of the entire multi-picture.
Since image characteristics of various sub-pictures outputted from the multi-picture have already been fixed, the aforementioned uniform adjustment of the output effect of the entire multi-picture by adjusting the output modes of the display device is not a type of differential adjustment, and it is usually impossible to provide all the sub-pictures with excellent visual experience because the effects of other sub-pictures are affected while the effect of one sub-picture is satisfied.